Earthworm – Castings

Q: I have mounds of what look like lilliputian guinea pig droppings all over our front yard. Can’t find any one who can I.D. Any thoughts?

A: I’m not sure how you’d know what lilliputian guinea pig droppings look like – but I can assure you that these creatures are not infesting your yard. The mounds are earthworm castings (droppings). As worms move through the soil, they ingest soil and organic matter. What comes out the other end of the worm is called a casting.

Earthworms are good for the soil because they incorporate organic matter from the surface into the lower soil region. This loosens the soil and makes passages for plant roots. Castings also contain plant nutrients.

Even though the castings are unattractive, you should be proud to have a good earthworm population. I recommend you simply mash the mounds with your foot or wash them away with a water hose.